Carbocyclic amines, in which a primary or secondary amine group is bonded to a carbon of the carbocyclic structure, commonly exhibit chirality, with one of the stereoisomers having a different utility, or a different degree of utility, from the other. Accordingly there is a need for efficient processes for separation of streoisomers of carbocyclic amines.
One class of carbocyclic amines which can exhibit chirality is the aminotetralins. Various 2-aminotetralin compounds are known to exert pharmacological effects on the nervous system of the mammalian body, by binding selectively to 5-HT receptors. One specific such compound, showing promise as an agent for treatment of Parkinson's disease, is N-0923, a chiral 2-aminotetralin-ethylthiophene compound of formula: ##STR1##
The chirality at C-2 is important in the activity of this and similarly useful 2-aminotetralins, and synthetic methods for its production need to be capable of producing the specific stereoisomer in substantially pure form. A key intermediate in the chemical synthesis of compounds such as N-0923 is (S)-5-alkoxy-2-aminotetralin hydrochloride of formula I: ##STR2##
where R represents lower alkoxy (in the specific case of N-0923 preparation, R is methoxy). Producing the substantially pure (S) enantiomer of this intermediate compound is necessary, in the preparation of N-0923 from it.